I disagree with the assumption that your need for connection with T is a 'want' rather than a 'need'. I fully believe that you experience it as an all consuming need. From what I can see it seems like it is your primary defence (way to soothe your emotions) against pain. Focusing on your relationship with T is a great way to avoid exploring the ton of issues you are burying about your relationship with your mom. And I do believe you experience it as an all-pervading need - I believe all your mom stuff is simple that unbearable.

One comment you made had me thinking. You said 'I didn't want to tell her I was sad because I wanted her closer to me."
Rhetorical questions for you (as in you don't have to answer here, but just think about them for yourself):

Do you feel that T will somehow 'move away' from you if you experience 'negative' emotions?
How did your mom react when you were sad or angry? Did she support you? Soothe you? Emotionally abandon you? Ignore you?
Who soothed you as a child? How?
If you do believe T will 'move away' from you if you feel sadness etc, does this impact on your ability to express feelings in therapy?